The effects of small ice crystals on the infrared radiative properties of cirrus clouds

To be successful in the development of satellite retrieval methodologies for the determination of cirrus cloud properties, we must have fundamental scattering and absorption data on nonspherical ice crystals that are found in cirrus clouds. Recent aircraft observations (Platt et al. 1989) reveal that there is a large amount of small ice particles, on the order of 10 micron, in cirrus clouds. Thus it is important to explore the potential differences in the scattering and absorption properties of ice crystals with respect to their sizes and shapes. In this study the effects of nonspherical small ice crystals on the infrared radiative properties of cirrus clouds are investigated using light scattering properties of spheroidal particles. In Section 2, using the anomalous diffraction theory for spheres and results from the exact spheroid scattering program, efficient parameterization equations are developed for calculations of the scattering and absorption properties for small ice crystals. Parameterization formulas are also developed for large ice crystals using results computed from the geometric ray-tracing technique and the Fraunhofer diffraction theory for spheroids and hexagonal crystals. This is presented in Section 3. Finally, applications to the satellite remote sensing are described in Section 4

Characteristics of cloud-to-ground lightning activity over Seoul, South Korea in relation to an urban effect

Cloud-to-ground (CG) lightning flash data collected by the lightning detection network installed at the Korean Meteorological Administration (KMA) have been used to study the urban effect on lightning activity over and around Seoul, the largest metropolitan city of South Korea, for the period of 1989–1999. Negative and positive flash density and the percentage of positive flashes have been calculated. Calculation reveals that an enhancement of approximately 60% and 42% are observed, respectively, for negative and positive flash density over and downwind of the city. The percentage decrease of positive flashes occurs over and downwind of Seoul and the amount of decrease is nearly 20% compared to upwind values. The results are in good agreement with those obtained by Steiger et al. (2002) and Westcott (1995). CG lightning activities have also been considered in relation to annual averages of PM<sub>10</sub> (particulate matter with an aerodynamic diameter smaller than 10 μm) and sulphur dioxide (SO<sub>2</sub>) concentrations. Interesting results are found, indicating that the higher concentration of SO<sub>2</sub> contributes to the enhancement of CG lightning flashes. On the other hand, the contribution from PM<sub>10</sub> concentration has not appeared in this study to be as significant as SO<sub>2</sub> in the enhancement of CG lightning flashes. Correlation coefficients of 0.33 and 0.64 are found between the change in CG lightning flashes and the PM<sub>10</sub> and SO<sub>2</sub>, respectively, for upwind to downwind areas, suggesting a significant influence of the increased concentration of SO<sub>2</sub> on the enhancement of CG flashes

Insulin-Like Growth Factor-I Stimulates Histone H3 and H4 Acetylation in the Brain in Vivo

IGF-I is essential to normal brain growth and exerts actions on neural stem cells and each major neural cell lineage. Whereas many studies show that IGF-I regulates gene expression, mechanisms by which it modulates transcription have not been explored. Chromatin modifications, such as histone phosphorylation, acetylation, and methylation, are known to be important initial steps in gene regulation, and acetylation of histone H3 and H4 is associated with gene activation. In this study, we show that IGF-I modulates the acetylation of H3 and H4 histones in the brain of two transgenic mouse lines and that these effects are associated with activation of the phosphoinositide 3-kinase/Akt signaling pathway. This provides evidence that the chromatin architecture modification contributes to the action of IGF-I on gene expression in the mammalian central nerve system

The Influence of Group Investigation Learning Model on College Students Learning Motivation Towards Environment Education

This study aims to analyze the influence of group investigation (GI) model on learning motivation of Student Environmental Education. This type of research is quasi experiment with non equivalent control group posttest only design. Research subjects consist of 2 semester students (2 classes) selected based on the value of Middle Semester Exam (UTS) odd semester of academic year 2017-2018 which has the average value is almost the same (homogeneous). The control class uses lecture and discussion models, while the experimental class uses the GI model. The instrument used to measure learning motivation is A Manual for the Use of the Motivated Strategies for Learning Questionnaire (MSLQ) developed by Pintrich et al. Further data obtained were analyzed by using Independent Sample T-Test Test with the help of SPSS 16.0 for Windows program. The results of this study indicate that there is a significant influence of GI model on the motivation to learn the environment of mahMahasiswa. It was based on the analysis results of the Independent Sample T-Test Test that showed the p-level 0.000. The p-level value is less than 0.05 (p <0.05). Key words: Group Investigation model, motivation to learn Environmental Education Studen

Virtual-pion and two-photon production in pp scattering

Two-photon production in pp scattering is proposed as a means of studying virtual-pion emission. Such a process is complementary to real-pion emission in pp scattering. The virtual-pion signal is embedded in a background of double-photon bremsstrahlung. We have developed a model to describe this background process and show that in certain parts of phase space the virtual-pion signal gives significant contribution. In addition, through interference with the two-photon bremsstrahlung background, one can determine the relative phase of the virtual-pion process

Structural transition in epitaxial Co/Cr multilayers as studied by X-ray absorption spectroscopy

[[abstract]]We have performed Cr and Co K-edge x-ray-absorption measurements to investigate the dependence of local electronic and atomic structures on the Cr-layer thickness in epitaxial Co (40A)/Ct (t~) (t~ = 2, 3, 5, 7, and 9A) multilayers. The Cr K x-ray absorption near edge structure (XANES) spectra of Co/Cr multilayers indicate an abrupt transition of the Cr layer from a bcc structure to a hcp structure when the thickness of the Cr layer is decreased down to -5A or three atomic layers. The structural transition and bond-length distortion in Cr and Co layers observed in the extended x-ray absorption fine structure (EXAFS) measurements are consistent with the XANES results.[[notice]]補正完畢[[journaltype]]國外[[booktype]]紙本[[booktype]]電子版[[countrycodes]]US

Aerostructural Optimization of a Transonic Compressor Rotor

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77121/1/AIAA-15397-760.pd